Electrolytic cell



June 20, 1939. H. E. RHODES 2,163,262

ELECTROLYTIC CELL Filed Aug. 9, 1935 INVENTOR llaaurd Z. Y/zozk's BYATTORNEYS QQQQ CM 451/4001 $7643 PatentedJune-ZO, 1939 I D ELECTROLYTICCELL Howard E. Rhodes, FloraLPar-k, N. Y., assignor to Aero'voxCorporation, ration of New York Brooklyn, N; Y., a corpo- ApplicationAugust 9, 1935, serial No. 35,474

7 Claims.

My present invention relates to electrolytic cells, and primarily toelectrolytic condensers of the so-called wet type; An object of theinvention is to' provide a venting device for an electrolytic cell, moreespecially of the wet type, which precludes the leak or escape of theliquid contents or any'part thereof,

even though the vent be held downward, and'yet affords adequate escapefor gas pressure that may be evolved during use.

Another object is to provide a device of the above type which shall beinexpensive in construction, which afiords no protrusions mechanicallyvulnerable in handling or of ungainly appearance, but which on thecontrary affords an attractive all-metal exterior, not subject toappreciable deterioration after successive ventings and which affordssubstantial venting protection throughout the effective life of thecell.

Another. object is'to provide a device of the above type in which novisible deposit occurs of salt entrained residue from droplets ofelectrolyte with gas during venting. v

Another object is to provide an anode structure for a wet cell such asan electrolytic condenser which' is simple and inexpensive inconstruction, the elements of which are mechanically secure and notsubject to deterioration after extensive use, and which afiords acondenser of superior power factor.

In the accompanying drawing, in which are shown one or more of variouspossibleembodi ments of the several features of the invention,

Fig. 1 is a. view in longitudinal cross-section of a condenser accordingto the present invention, Fig. 2 is a transverse sectional view taken online 2--2 of Fig. 1, 'Fig. 3 is a perspective view of the anode unit,and

Fig. 4 is a dropped perspective view of the parts making up the ventingunit.

Referring now to the drawing there is shown in Fig. 1 a wet electrolyticcondenser comprising the cathode can I, ordinarily of aluminumgthe openend of which is illustratively shown with a rigid insulating closureplug H which may be of vulcanite, hard rubber or the likeand which has athreaded extension l2 that serves'for mounting the unit in conventionalmanner. The plug rests against a unitary shoulder I3. in the can and issecured in place by rolling the rim of the can, as at H, against a softrubber gasket 15 lodged in a rabbet in the plug I l.

Mounted on the rubber -plug is the anode structure, which accordingto-the present invention is of special design. The riser in thisembodiment comprises a metal rod 18 having an enlargement l'l resting ina corresponding depression l8 in the closure plug and having its lowerend upset at I9 over the terminal lug 20 against the lower end 01' plugl l.

The riser, the main length of which is preferably flatmounts the anodeplates proper. For this purpose it is ordinarily preferredto employthree generally identical plates 2|, 22 and 23, the inner ends of whichare superposed as at 24 over the riser and are rigidly attached theretoby hollow rivets 25 extending through the riser and said superposedplates to connect the elements into a rigid assembly.

Preferably the anode plates 'are in undulatory form, deeply corrugatedas at 26 to afl'ord an increased surface area of anode within the spaceconfines of the container. The general plane of each of the platespreferably radiates from the axis of the riser and said plates arespaced at uniform angular intervals 120 degrees apart as shown, althoughof course different spacing could be employed, andfour or more of saidplates could be used, if desired. Preferably the riser, the plates andthe rivets are all of the same film forming metal, ordinarily aluminum,and the plates, rivets and riser are all formed with the usualdielectric film.

The outer ends of the corrugated anode plates would press against theinner wall of the can In in the assembled construction and tend toshortcircuit the condenser. To prevent such shortcircuiting aninsulating liner sleeve .8 perforated as at 29 is disposed within thecan and is contacted by the outer extremities of the several anodeplates.

The cell is charged with' a liquid electrolyte solution 30 to a pointabove the level of the anode which it submerges. This solutionordinarily is an aqueous one and may be the conventional one of boricacid and sodium borate.

According to the present invention, the average distance from the anodeplates to the can is relatively small, for which reason the course ofcurrent flow between the anode and the cathode has a short average paththrough the electrolyte, so that the series resistance is kept at lowvalue and the condenser with the present anode structure therefore hassuperior power factor characteristics.

In the operation ofelectrolytic condensers, gas pressure may developfrom time to time while the condenser is on voltage. This may resultfrom excessive heat in the condenser causedwhich must be relieved,without, however, afiordrubber and 2 amazes by current leakage throughfilm, or by the to the operationabove described, for. were saidproximityof other heat generating apparatus rubber washer permitted to balloon upunder such as transformers andtubes. The expansion conditions of.pressure and to conform to the of the liquid and especially of the air'inside the shape of the inside of thehood 3'! before venting,

condenser results in the evolution 'of; pressure electrolyte might creepbetween the can and the 5 impair .the return of the rubber to its ingany opening that might' permit: any of the flat' condition. i

liquid electrolyte te -leak out. v f While the dished washer 35 'asdescribedis In the specific embodiment shown, the closed preferred,sinceit afl'ord's the auxiliary inner end of the containenshownuppermost in Fig. 1, has a central aperture 3,l therein 01% to inchmetalwasher for the rubber washer would serve in diameter and anuprising peripheral lip 32. A andis within the scope of certain of theclaims flexiblerubber washer 33 rests on'the end wall e einwith itsperiphery substantially in contact with It is, 'of course,-understoQthat h' the inner wall f the lip 32. Said washer has scope'oftheinvention'in its broader aspects, the a minute pinhole show'n exagerated in size at hood element. and the auxilia y 34 which, by virtueof the elasticity of the rubber, o d d t e eby might e' mi edisnormally. closed n i su erposed It is also understood that the flexible,elastic -over the rubber washer 33 is a dished spring Washer d theProtective Washer Could be 518- metal washer 35 of smaller diameter,preferably D Parts O the n i' the d seal above described, it isunderstood that a flat 1 v protection afof phosphor bronze with acentral aperture 35 therein of substantially the size of the aperture 3|in the end wall of the; can. Superpo'sed over the rubber washer 33 andspring washer 35 is a protectivejsheet metal domed hood- 31 which has aflat rim 38, superposed over the rubber washer 33 and a concentricshoulder 39 engaging the upstanding rim 4!] of the dished washer 35.

The upstanding lip 32 of the'can' is rolled in ward as at to engage theflange 39 of the dome and to. exert'pressure against the rim of therubber washer 33, and'incidentally to ,press the dished metal washeragainst rubber-washer 33 about the aperture 34 Minute venting apertures42 are provided near the outer part of the dome 31.

The construction described has the advantage that the simple rubberjwasher '33 is cut from rubber sheet stock and that the washer 35 andthehood 31 are simple metal ll'he can structure set "forth is quitesimple and inexpensive; the extruding die being simply con--'structed'with a peripheral depression to permit some of the metal fromthe.slug to be forced 'thereintoto form the lip- 32.

No liquid will ever escape from the unit, re-

gardless whether the device be vigorously, shaken,

orsubjected to such heat as is incurred in trans* portation or use. Thisis due tothe fact that the rubber-washer 33 forms a satisfactoryleak-tight gasket,not only at'the inner portion thereof resilientlyengaged by the depressed middle of the. dished washer 35, but also atthe outer periphery thereof clamped 'by the hood rim 38. If in the 55.

course of operation, gas pressure'is evolved, thewithout departing fromthe scope of the invention in its broadest aspects; and that the entireventing imit whether at the end or at the 'side.-.

construction and that the particular anode construction' shown,describedand' claimed may be 35 used with vents other than that made10,1115": of the subjects of this application.

It will thus be seen that there is herein'described apparatus in whichthe several featuresof this in? vention are embodied, and whichapparatus in its action attains the various objects of the-invention andis well suited to meet-the requirements of practical use. -As manychanges'could'be made in the above construction, andmany'apparentlywidelydifferent embodiments of this invention could bemade without departing from the scope thereof, it is intended that allmatter contained inthe above description or shown in the accompanyingdrawing shall be interpreted limiting sense. 7

Having thus described my invention, what I a claim as new and desire tosecure by Letters Pat.-

ent, is: e

, 7 25 and claimed 18 paras illustrative and not in a j l. A ventstructure for an electrolytic cell, 'comrubber washer 33- is caused toballoon or how. prising acontajner having an upstandingperiphoutwardfrom the region of aperture 34 and eral lip at the outerend thereof and an end wall through e aperture 35 0f Washer In thiscontinuous except for a'relativelysmall axial perand thence escapesthrough the vents 42. After bowing operation the'pinhole 34 spreads openforation, a flexible washer superposed over said and the gas isdelivered into'the domed hood vious near its middle, a rigid hood memberprm tecting the exposed face of said washer and having a rim in contacttherewith, said container having a lip rolled over said rim to maintainthe parts in assembled relation.

2 In. a wet electrolytic condenser structure, a can having aperforatediend wall continuous except for a relatively small am'alperforation and with a peripheral lip rising from said wall, a

the gas pressure has been released the bowed rubber washer 33 snaps backinto its plane, by virtue of its elasticity, with the original pinhole34 closed.

In venting gas pressure, it is possiblethat minute droplets or spray ofelectrolyte will be entrained with the gas, to settle about thepinhole'of the rubber washer 33, leaving a white deposit of saltthereat. Such salt deposit, howflexible washer centrally gas perviousunder pres- 70 ever, is invisible exteriorly and the exposed vent sureand superposed over said end Wall, and means i holes 42 of the domeremain at all times clean clamping said Washer in position immediatelyandfree from salt or other deposit. about said gas pervious area tolimitthe fiexure The spring washer 35 is desirable to restrict to the regioncovered by said perforation in the the movement o he rubber washeraccording can, and a protective hood covering said washer '75 perforatedend wall, said washerbeing gas per- 60' and said clamping means, saidlip being rolled to exert clamping pressure on the rim of said washer.

3. In a wet electrolytic condenser, a can having an end wall continuousexcept for a relatively small axial perforation, and a peripheral liprising from the periphery of said end wall, a flexible rubber washerover said end wall and having a small central perforation, a metal hoodmember protecting said washer and having a peripheral flat rimsuperposed over the peripheral portion of said washer, said lip beingrolled inward over said rim, said hood having small ventingperforations. a a

4. In an electrolytic condenser, the combination of a can having an endwall continuous exceptfor a relatively small axial perforation and anupstanding peripheral lip, a flexible rubber washer having a centralminute hole superposed over said perforation, a metal washer having acentral aperture and superposed over said rubber washer to protect thesame, said lip being rolled over and serving to clamp said two washersin position.

5. An electrolytic condenser comprising a can having a centralperforated end wall and having a peripheral upstanding lip, a flexiblerubber washer having a central pinhole and resting against said endwall, a metal washer having a central aperture and superposed over saidrubber washer, and a metal hood having a flat rim superposed oversaidmetal washer and affording minute venting apertures, said lip beingrolled inward to clamp said hood against said metal and said rubberwashers.

6. An electrolytic condenser comprising a can having an end wall with aperforation, a flexible rubber washer superposed over said end wall andhaving a pinhole at the region of said perforation, a dished springwasher having its outer rim upstanding and perforated in registry withthe perforation in said end wall, and a metal hood member exertingpressure upon the upstanding rim of said dished washer and rigidly fixedat its rim to said end wall.

'7. In an electrolytic condenser, the combination of a can having acentral perforated unitary end wall and an upstanding peripheral lip, aflexible rubber washer resting against said end wall and substantiallycontacting the inner periphery of said lip and having a central pinhole,a phosphor-bronze, centrally perforated dished washer superposed oversaid rubber disk with its outer rim upstanding, a metal hood memberhaving a shoulder engaging said rim and having a flat rim against saidrubber washer, said lip being rolled over. against said rim to retainthe parts in assembled condition.

HOWARD E. RHODES.

